This invention relates to an ophthalmoscope, i.e., an instrument for viewing the interior of the eye. More particularly, the invention provides a wide-angle ophthalmoscope which achieves more uniformly illuminated imaging of the eye fundus than heretofore possible.
The invention thus provides a wide-angle ophthalmoscope having a superior uniformity of image intensity at the ophthalmoscope viewing location, as compared to prior devices of this kind. Due to these and other advantages set forth below, an ophthalmoscope embodying the invention enables superior viewing of the entire retina, and photographing it, in a single image with a single placement of the instrument.
My previous patents and patent applications, noted above, describe wide-angle ophthalmoscopes having improved constructions for both illumination through the crystalline lens and transillumination through the sclera of the patient. With the first type of illumination there is often a noticeable diminution of illumination at the posterior pole of the fundus as well as the requirement for significant dilation of the patient's pupil; with the second there is an intensely bright spot on the image corresponding to the fundus portion adjacent the sclera location where transillumination occurs.
Accordingly, it is an object of this invention to provide a wide angle fundus-viewing instrument in which the optical intensity of the fundus image, as seen from the viewing location, is more uniform than in prior devices of this kind.
A further object is to provide improvements in a transillumination type ophthalmoscope that yield such improved image uniformity and that can be provided as add-on features to existing ophthalmoscopes of this type.
It is also an object of this invention to provide a wide-angle ophthalmic instrument using illumination applied through the eye sclera and which provides an image having relatively uniform brightness. It is a further object to provide such an instrument capable of providing such uniform image brightness with subjects having eyes of different geometries, i.e. different sizes and shapes.
Another object of the invention is to provide an ophthalmic device of the above character which is of relatively simple and low cost construction, and which is relatively easy to operate.
Other objects of the invention will in part be obvious and will in part appear hereinafter.